Velocity,
I won't try and make the case that the model, as a whole, is the most reliable ever, but I gotta tell you, I own a Ruger P90 and that gun has my complete and total confidence. Outside of just purely faulty rounds, I have yet to find anything that it won't eat up, and there was even one occasion that it cycled ammo that wouldn't cycle in any of the other .45's on the range. I absolutely, one-hundred percent, no questions or exceptions asked or given, have faith that that gun will fire every time I pull the trigger. Now, thats just about its reliability, and there are things about it I don't like. First, grip panels suck (replace with Hogue wrap arounds, and you have a winner though). Second, its a big pistol, and thus not suitable for everyone. Third, even though I personally feel its a good looking gun, many disagree. On the other hand, its very affordable, and even better, its pretty common, so it should be fairly easy to find one used at a pawn shop or someplace for even cheaper. In good shape, I personally have seen them as low as just a couple of hundred bucks, although the average used price around here is probably more in the $250-300 category. Anyway, thats just my two cents, and I can guarantee that others will have had bad experiences with them, but if you were to say "Tim, what .45 should I buy?", I would say without hesitation, "P90".
Timbo